Updated 27 August 2024

I have an irrigation system with a water break-tank containing ~ 400 litres which is used to supply an unattended pump, the problem I needed to solve was what if there is a leak or burst in the pump enclosure, I don’t want the tank to empty.

The break-tank does have a base valve and I saw on Aliexpress that they did 12v clamp on motorised heads which can convert a manual lever valve into an automatic valve, enabling both electrically operated, opening and closing, these cost £10.42 including VAT and postage I thought I’d give one a go and ordered the 3/4″ clamp version.

When the unit arrived, it became obvious that it physically wouldn’t fit on the base valve, so I bought a 22mm full bore lever valve, (Toolstation part 92144), and fitted this upstream of the base valve giving plenty of room for the head to mount.

Fitting of the head is very easy with a clamp being used around the pipe to hold it in place and the moveable arm has adjustable pins for accurate lever alignment.

On the base of the head is a ‘ring pull’, pulling this disengages the motor enabling manual operation of the valve.

The video is a bit rough as this was the first actual test after building the control system and triggering the valve using a licked finger on the sensor.

The motorised head has no positional output, once power is applied, it will drive 90^o in one direction and stop, reversing the motors polarity, will cause the motor the drive 90^o in the opposite direction and stop, all very simple.

Home Assistant monitors my irrigation system, so it was a logical step to include the leak detection system into that, however, it will run without Home Assistant from the Shelly App.

The Shelly Uni has two outputs and two inputs, each of the outputs was used to trigger a relay for valve open and valve close.

One of the inputs was connected to a probe with separated contacts, if the contacts are bridged (wet finger), the Shelly detects this which was perfect, the other input I used with a reed switch so that I could open and reset the valve with a magnet, I chose this way so that I didn’t have to drill the IP rated enclosure, (Toolstation part 91800, 80 x 80 x 50mm), the circuit board will live in.

The above image is of the test leds simulating the motor polarity with the finished circuit inside a IP65 rated enclosure.

Finished water leak protection valve wired up to relays within IP rated enclosure.

12v from PSU to Shelly and relays from motor control box, in the top right you can see the white water leak sensor.

The Shelly Uni has a timed output facility, also the inputs can be linked to the outputs, this means that if the leak sensor detects, the associated output will operate for a preset time, in my case I used 10 seconds for both open and close duration.

Below is my Home Assistant irrigation status dashboard this shows the status of the leak detection sensor and the valve position, (done by virtual entity toggling status, rather than valve feedback).

When a leak is detected in the pump enclosure, the break-tank base valve will close and at the same time, the pump contactor will be interlocked to prevent operation.

An automation linked to my local calendar, will ‘exercise’ the base valve to close, then open, monthly, this automation will be overridden if the irrigation system is in use or a leak has already been detected.

I can either manually trigger the valve to open by offering a magnet to the side of the control box, or use Home Assistant, once the valve is triggered to open, the interlock comes off the pump contactor.

I have also set up Home Assistant to send a notification to my mobile should a leak be detected not only from the pump enclosure, but from a wireless leak detectors placed by my heating boiler and washing machine.

The mobile alert action below is for the pump enclosure and is triggered when the valve closes on water detection: